Actuating mechanism



8 Sheets-Sheet 2 Filed June 22, 1956 I fj y gw M IIL 'ATTORNEY Sept. 10,1957 w. F. DEHN ACTUATING MECHANISM Filed June 22, 1956 man n! 8Sheets-Sheet 3 jaz y. 11.

v INVENTOR WILLIAM F.DEHN

AT TOR NEY w. F. DEHN ACTUATING MECHANISM Sept. 10, 1957' 8 Sheets-Sheet5 Filed June 22, 1956 \TIDOO INVENTOR WILLIAM F. DEHN ATTORNEY Sept. 10,1957 w. F. DEHN 2,805,579

ACTUATING MECHANISM 8 Sheets-Sheet 6 j g? 32. spy/3 p35 6/ Filed June22, 1956 INVENTOR WILLIAM F. DEHN AT TORNEY Sept. 10, 1957 Filed June22, 1956 8 Sheets-Sheet 7 INVENTOR WILLIAM F. DEHN BY 96w ATTORNEY Sept.10, 1957 w. F. DEHN 2,805,579

ACTUATING MECHANISM- Filed June 22, 1956 8 Sheets-Sheet 8 2 .46. fig" .ZM8 4 //3 M I M8 //3 M/ xxxyxxm E INVENTOB WILLIAM F. DEHN.

BY m

ATTORNEY United States Patent ACTUATING MECHANISM William F. Dehn,Wauwatosa, 'Wis., assignor to Allen- Bradley Company, Milwaukee, Wis., acorporation of Wisconsin Application June 22, 1956, Serial No. 593,167

17 (llaims. (Cl. 74-99) This invention relates to an actuatingmechanism, espe cially but not exclusively adapted to produce a shortand early trip of a switch of the type biased to return to its originalposition when not being actuated by the trip actuating mechanism; andresides more particularly in an actuating mechanism which includes arotatable member capable of limited rotation back-and-forth underexternal actuation; a substantially linearly reciprocable followermember, for the output of linear motion to an actuated mechanism; andmeans for converting the rotary motion of the rotatable member intotranslation of the follower member, said converting means comprising: apair of cams, with their cam-surfaces facing each other, and relativelymoveable toward each other in response to the rotation of the rotatablemember; means guiding the reciprocation of the follower member; a pairof interen'gaging rollers, journaled on the follower member, side byside laterally with respect thereto, and each rolling on the cam-surfaceof one of the cams; and means (preferably resilient) biasing thefollower member to move in one given direction along the guide means;the cam-surfaces being so positioned and having such conformations as,by their pressure on the rollers, to tend to move the follower memberalong the guide means in the direction opposite to the given direction.

In one species of the invention one cam of the pair is motionless andthe other cam of the pair is moveable toward the first, and the tworollers are shiftable laterally with respect to the follower member. Inthe preferred variant of this species, there are two such pairs of cams,one of which pairs functions when the rotatable member is rotated in onedirection from dead center, and the other of which pairs functions whenthe rotatable member is rotated in the opposite direction from deadcenter.

In a second species of the invention the two cam surfaces aresymmetrical with respect to the line of translation of the followermember, and move toward each other in unison, when the rotatable memberis rotated in either direction from dead center. In this species, thetwo rollers are loosely journaled to permit them to always interengage,and to permit some slight further lateral shift to take account ofdilference in lever-arm.

It is the principal object of the invention to provide a. novel andsimple conversion mechanism for the tripactuation of a switch of thetype usually referred to as spring-return, so that the conversionmechanism and the switch proper shall together constitute aspring-return limit-switch.

It is a further object of the invention to provide such a mechanism, inwhich the rotary motion of an externally actuated rotary member will beconverted into translation of a switch-tripping member, in such mannerthat the trip will occur quickly during a short angular travel of therotatable member, with but slight overtravel of the following memberafter it has tripped the switch.

However, it should be understood that the invention is not limited totheactuation of a spring-return limit-switch,

nor any kind of switch, nor even any mechanism springreturned, but maybe used with any actuated mechanism (not necessarily electrical) whichthe invention is capable of actuating, such for example as a cut-out,either automatic reset, or even hand reset. Nor is the invention limitedto producing any particular sequence of speeds of operation. To this endthe cam-surfaces may have any appropriate configuration.

These and other objects and advantages ofthe invention will appear inthe description to follow. In the description, reference is made to theaccompanying drawings which form a part hereof, and in which there areshown, by Way of illustration and not of limitation, two specific formsin which this invention may be embodied.

In the drawings:

Fig. l is an actual-size front elevation of the operatinghead(containing the actuating mechanism of the present invention), mountedon top of the actuated switch-proper.

Fig. 2 is an actual-size side elevation of the same, viewed as seen fromthe right in Fig. 1.

These first two figures are applicable to either species of theinvention.

Fig. 3 is an enlarged front elevation, of a portion of theoperating-head of the first species of the present invention, mounted ontop of an actuated switch-proper (which may constitute the mechanismactuated by either species), the lower part of the figure being cut-awayto show the actuating connection between the two mechanisms.

All the remaining figures are to the same enlarged scale as Fig. 3,except that Figs. 27 to 30 and 46 to 49 are to an even more enlargedscale. I

Fig. 4 is a plan view of the operating-head casing of the first species.

Fig. 5 is a rear elevation of said casing, showing the centering-springassembly in place.

Fig. 6 is a front elevation of said casing.

Fig. 7 is a vertical section of said casing, viewed as though out alongthe line 77 of Fig. 4.

Fig. 8 is a vertical section of said casing, viewed as though out alongthe line 88 of Fig. 7.

Fig. 9 is an edge elevation of the follower of the first species.

Fig. 10 is a side elevation of said follower.

Fig. 11 is a plan view of said follower.

Fig. 12 is a side elevation of the double moveable cam of the firstspecies.

Fig. 13 is a plan view of said cam.

Fig. 14 is an end view of said cam.

Fig. 15 is a left-hand end view of the shaft of the first species.

Fig. 16 is a side elevation of said shaft.

Fig. 17 is a right-hand end view of said shaft.

Fig. 18 is a section of said shaft, viewed as though out along the line18-18 of Fig. 17.

Fig. 19 is a side elevation of one of the two identical spring leverscommon to both species of the present invention.

Fig. 20 is an edge elevation of said lever.

Fig. 21 is a side elevation of the spring stop common to both species.

Fig. 22 is an edge elevation of said spring stop.

Fig. 23 is a side elevation of the centering spring common to bothspecies.

Fig. 24 is an elevation of said spring, as seen from the right in Fig.23.

Fig. 25 is a vertical section of the operating head to the firstspecies, viewed as though out along the line 2525 of Fig. 26. V

Fig. 26 is a vertical section of the same, viewed as though out alongthe line 26-26 of Fig. 25. i

Fig. 27 is a much enlarged-portion of the vertical section of Fig. 26,showing the positions of the crucial elements of the actuating mechanismof the first species, when the shaft is on dead-center.

Fig. 28 is the same, with the shaft rotated degrees counter-clockwisefrom dead-center.

Fig, 29 is the same, with th shaft rotated 40 degrees counter-clockwisefrom dead-center. N

Fig. 30 is the same, with the shaft rotated 55 degrees counterclockwisefrom dead-center.

Fig. 31 isa plan view of theoperating-head casing of the second speciesof the present invention.

. Fig. 32 is a vertical section of said casing, viewed as though outalong the line 32'-32 of Fig. 31.

Fig. 33 is a vertical section of said casing, viewedas though cutalongthe line 33'-33 of Fig. 32.

; Fig. 34 is an edge elevation of the follower of the second species.

Fig. 35 is a side elevation of said follower.

Fig. 36 is a plan view of said follower.

' Fig. 37 is an edge elevation of one of the two identical cams of thesecond species.

Fig. 38 is a plan view of said cam.

Fig. 39 is a side elevation of said cam.

Fig. 40 is a left-hand view of the shaft of the second species.

Fig. 41 is a side elevation of said shaft.

Fig. 42 is a section of said shaft, viewed as though out along either ofthe .two lines 4242 of Fig. 41.

Fig. 43 isa plan view of said shaft.

Fig. 44 is a vertical section of the operating head of the secondspecies, viewed as though cutalong the line 44-44 of Fig. 45. a

Fig. 45 is a vertical section of the same, viewed as though out alongthe line 45--45 of Fig. 44.

Fig. 46 is a much enlarged portion of the vertical section of Fig. 45,showing the positions of the crucial elementsof the actuating mechanismof the second species, when the shaft is on dead-center.

Fig. 47 is the same, with the shaft rotated 5 degrees counter-clockwisefrom dead center.

Fig. 48 is the same, with the shaft rotated 40 degrees counter-clockwisefrom dead-center.

Fig. 49 is the same, with the shaft rotated 55 degrees counter-clockwisefrom dead center.

Throughout the description, the same reference number is applied to thesame member or similar members.

Referring now to the drawings, more particularly Figs. 1 and 2, whichare drawn to actual size, it will be seen that 51 is the operating-headcasing, which serves a support for the actuating mechanism of thepresent invention. This actuating mechanism, and the internal details ofthe casing, differ between the two species which will be hereinafterdescribed; but the external appearance of the two sorts ofoperating-heads is practically the same.

52 is the case which contains the actuated switch,

which can be the same for both species.

Operating-head casing 51 can be secured to switch case 52 (oriented inany one of four directions) in any convenientmanner such asfour screws53, which also serve to hold in place domed cover-plate 54. When theoperating-head is not attached to the actuated switch, coverplate 54 isheld in place by two small drive-screws 55.

Bushing 56 is secured to casing 51 in any convenient manner, such as byscrews 57. Through this bushing, there projects shaft 58, to which shaftthere is secured in any convenient manner (as by clamping pin 59 and nut60) a lever arm 61, at the extremity of which. there is journaled aroller 62.

The impact against this roller 62 of some moving stop or stops (notshown) is what supplies ,the external actuation to impart a limitedrotation to shaft 58, thus setting in motion asuccession of elements totrip and untrip the actuated switch.

. Referring nowto Fig. 3, there will be described. a mechanism which maybe employed to operationally connect the actuating mechanism within theoperating-head to the actuated mechanism within the switch, if and whenthe invention is used with such a switch.

63 is a vertically moving plunger, the vertical reciprocation of whichshifts the switch from one to the other of its two settings. The detailsof this internal operation of the actuated switch are shown anddescribed in applicants copending application, Serial No. 487,096, forSnap Action Mechanism, filed Feb. 9, 1955, and in copending applicationof applicant and Wilson, Serial No. 364,544, for Contact Actuating QuickAction Switch, filed June 29, 1953, to which applications reference ishereby made.

Plunger 63 is shown in Fig. 3 hereof in its extreme lower position. Itis biased by a spring (not shown herein) to assume its extreme upperposition.

64 represents the bottom ends of two of the four legs of a doublybifurcated follower. This follower is shown in Fig. 3 in its lowermostposition which is the position it assumes when shaft 58 is ondead-center. Rotation of this shaft, in either direction fromdead-center, raises the follower by means which will hereinafter bedescribed.

Operational contact between plunger 63 and follower 64 is maintained byan actuator, the head 65 of which engages the legs of follower 64, andthe point 66 of which engages the top of plunger 63.

A narrow male-threaded portion of head 65 extends downwardly through thecenter of a diaphragm 67 of flexible stretchable oil-impervious materialsuch as rubber and thence through a hole in the. top of an invertedcylindrical cup 68. Onto this male-threaded portion of the head, thereis screwed female-threaded actuator-point 66, thus clamping diaphragm 67between head 65 and point 66. The outer edge of diaphragm 67 is in turnclamped between the lower surface of casing 51 and the upper surface ofcase 52.

Thus the assembly, thus described, effectively seals off the escape ofoil from the actuating mechanism in headcasing 51, to the actuatedswitch mechanism in case 52; and yet permits downward motion of follower64 to be freely transmitted to plunger 63, and permits upward motion offollower 64 to permit plunger 63 to move freely upward under theinfluence of its own spring. In other Words, the follower and theplunger, with the actuator between them reciprocate vertically as aunit, and yet permit upward overtravel by follower 64 when plunger 63has reached its upward limit. For further showing and description ofthis diaphragm-actuator assembly, see above-mentioned application,Serial No. 487,096.

Inasmuch as the actuating mechanism of the present invention can beemployed with other sorts of actuated mechanism than the spring-returnswitch above referred to and partially described, other and differentconnecting means than the actuator 65 to 68, or no such means, could beemployed, and another and different actuated element than the plunger 63could be employed. But some means, either automatic or otherwiseactuatable, should be provided to return the actuated mechanism to itspro-actuated condition.

Operating-head casing 51 will now be described, with reference to Figs.4 to 8, 25 and 26.

First consider front elevation (Fig. 6) and rear elevation (Fig. 5).

69 are holes for shaft 58. 70 are holes for bushingscrews 56. 71 is acavity for a bearing 72, hereinafter described, for shaft 58.

73 is a cavity to hold the entire centering spring assembly, consistingof two spring levers 74, spring stop 75, and spring 76. 77 is a slot, tocontain the head of spring stop 75. 78 and 79 are shoulders, to arrestthe rotation of spring lever 74. The assembling of this assembly andoperation will be discussed hereinafter, in connection with Fig. 25.

Turning :now to Fig. 4, the plan view of casing 51, and the twoverticalsections thereof, Figs. 7 and 8, it will be 5 seen that 80 arefour holes for screws 53, and 81 are two holes for drive screws 55. 82is a vertical hole through casing 51. i

83 are four vertical ribs, defining four narrow vertical slots 84 andtwo wide vertical slots 85.

The upper portions of ribs 83 also constitute fixed cams, rigid withtheir support: i. e., the casing 51. The two left hand ones of the camscan be considered functionally as a single cam, inasmuch as they areidentical and function jointly. Similarly as to the two right hand08.1118.

The four narrow slots 84 serve to receive slidably the four legs 86 offollower 64. To avoid any possibility of attempting to assemble thecontents of casing 51 upsidedown, narrow slots 84 .are narrowed slightlyfurther at their bottom ends so that legs 86 cannot be inserted fromthat end.

At the bottom ends of-ribs 83 are cut-away portions 87, to permit theinsertion of the head 65 of the actuator, as described in connectionwith Fig. 3; but shoulders 88 prevent upward travel of the actuatorfurther than is necssary to permit the plunger 63 to trip the switch.

Figs. 9, 10, and 11 show respectively an edge elevation, a sideelevation, and a plan view of follower 64. As already mentioned, thisfollower has four legs 86. In each side there is a horizontal slot 89,to permit the axles 96 of rollers 91 to slide laterally, so that therollers can constantly engage each other and the respective camsurfaces,as will be hereinafter described. Each axle is free to slide lengthwiseof its roller. When the follower is assembled in operating-head casing51, the walls of hole 82 (see Fig. 4) maintain the axles in the rollers.

Figs. 12, 13, and 14 show respectively a side elevation, :a plan view,and an end elevation, of double moveable cam 92. This cam is rigidlyassembled to shaft 58, and rotates with it. The upper surface of thecam, from A to B, serves as a double earn-surface for one or the otherof rollers 91, as will be explained hereinafter, when discussing Figs.27 to 30. The surfaces from A to D, and from B to C, [are "concentricwith the axis G of the shaft. The surface from E to F fits crosswisediametrically to the shaft. There is a screw-hole 93.

Figs. 15, 16, 17, and 18 show respectively a left-hand end view, a sideelevation, a right-hand end view, and a cross-section, of shaft 58. 94is. a slot for the insertion of a screwdriver, to steady the shaft whenadjusting leverarm 61 on the shaft. 95 is a squared portion, to receivecertain elements of the centering spring assembly, as will hereinafterbe described. 96 is a screw-hole. 97 is a diametric transverse slot, toreceive the surface EF of cam 92. 98 are cut away portions, to avoidinterference with the cross-head 99 of follower 64 (see Fig. when thefollower is in its lowest position. 100 is a cut-away portion, for flatabutment of screw 101 (see Figs. 25 and 26).

Figs. 19 and 20 show respectively a flat elevation and an edge elevationof spring-lever 74. This lever has a hole 102 to engage squared-end 95of shaft 58, and a projection 103 to engage alternately the two ends ofcentering spring 76, and to stop against shoulders 78 and '79 in cavity73 of casing 51 (see Fig. 5).

Figs. 21 and 22 show respectively a flat elevation and an edge elevationof spring-stop 75. It has a circular hole 104, to permit free rotationof the shaft therein; a head 105 to fit in slot 77 of casing 51 (seeFig. 5) and thus hold spring-stop 75 against rotation; and a neck 106 toengage alternately the two ends of centering spring 76.

Figs. 23 and 24 show two elevations of centering spring 76, which is anested circular leaf-spring, severed as at 107.

The assembling of the operatinghead mechanism will now be explained,with particular reference to Figs. 25 and 26. Reference will also benecessary to some of Figs. 4 to 24, from time to time.

Shaft 58 is first inserted through holes- 69 in casing 51.

Bearing 72 and bushing 56 arethen applied over the left-hand end of theshaft, and are secured in place by screws 57. 7

Cam 92 is inserted, proper side up, into casing 51 from the top, withthe ends of the cam in the two slots 85, until surface EF of the camfits into transverse slot 97 of shaft 58, and the two are then rigidlyjoined together by screw 101, inserted from beneath. The sides of theends of cam 92, by bearing against the sides of slots 85, prevent thewithdrawal of shaft 58 in either direction. 1

The four legs 86 of follower 64 are then inserted from above into thefour slots 84, and the follower is dropped astraddle of shaft 58.

Lever 61 can be secured to the projecting end of shaft 58 by means ofclamping pin 59 and nut 60 (see Figs. 1 and 2) at any convenient time.It is usually secured inverted, for shipment.

The centering spring assembly is assembled as follows in cavity 73 ofcasing 51. With shaft 58 in the angular position shown in Figs. 5 and25, one of the two spring levers 74, then spring stop 75, and then theother spring lever 74, are slipped over the squared end 95 of shaft 58,with the head of the spring stop in slot 77 of the casing, and theprojections 103 of the two spring levers aligned with the neck 106 ofthe spring stop. Spring 76 is then opened up at severance 167, and isslipped in, surrounding the two spring levers 74 and the spring stop 75.The two severed ends of the spring butt against the sides of projections103 of the spring levers and neck 106 of the spring stop.

The centering assemblage operates as follows to center shaft 58. Theshaft can be rotated about 55 degrees counterclockwise or clockwise,until projections 163 strike shoulders 78 or 79 respectively. The resultof counterclockwise rotation is shown dotted in Fig. 5. One severed endof spring 76 has been. pushed counterclockwise by projections 74, theother end remaining butted against neck 106, thus spreading the spring.The resulting tension set-up in the spring, tends to restore the shaftto deadcenter, i. e. the full-line position shown. Similarly withrotation clockwise.

The final step in assembly is to place cylindrical helical spring 108 ontop of follower 64, and to fasten cover plate 54 in place withdrive-screws 55. The dome 199 of the cover plate compresses helicalspring Hi8 slightly, and the back fiat portion of the cover plate holdsthe just described centering assemblage from falling out. Spring 108should preferably be twice as strong as the returnspring of the actuatedmechanism, or corresponding resistance-element, if any.

As introductory to a discussion of how follower 64 is caused toreciprocate, it should be noted that, from an operational point of Viewthe cam-surfaces of each pair of ribs 83 constitutes a singlecam-surface. When shaft 58 is rotated counterclockwise, rollers 91 areacted upon between one pair of cams, i. e.: the right-hand camsurface ofmovable cam 92, and the fixed cam-surface afforded by left-hand ribs 83;the left-hand cam-surface of cam 92 and the cam-surface of left-handribs 83 being inoperative. Vice versa, when shaft 58 is rotatedclockwise.

Thus there are seen to be two pairs of cams, one of which pairs engagesthe two rollers 91 when shaft 58 is rotated in one direction from deadcenter, and the other of which pairs engages the tWo rollers when theshaft is rotated in the opposite direction from dead center. Also it isseen that, of each pair of cams, one cam (i. e., that formed by ribs 83)is held rigid with respect to the support (i. e., operating-head casing51), whereas the other cam (i. e., that formed by one cam-surface of cam92) is movable with respect to the support.

The effect of counterclockwise rotation of shaft will now be discussed,as illustrative of the effect of rotation in either direction. IFollower 64 is reciprocated in the manner disclosed'in "greatlyenlargedFigs. 27m 30. Fig. 27 shows the position of the elements with shaft '58on dead-center. Figs. 28, 29, and 30 showthe changing position of theelements as the's'haft is rotated counterclockwise: degrees, 40 degrees,and 55 degrees, respectively.

It will be seen from Fig. 28 that, during the first 5 degrees ofrotation, actuator-head 65 has moved upward sufficiently to trip theswitch located in base 52, shortly thereafter being stopped by shoulders88, after which all further upward travel of follower 64 is overtravel.

Upward motion of the follower is effected by pressure on the rollers asthey are squeezed between the right-hand cam-surface of moveable cam 92and the cam-surface of left hand fixed earns 83, while the formercam-surface is being moved toward'the latter cam-surface by therotationof shaft 58.

In other words, each cam-surface presses on its respective roller 91 inthe direction of radii extending from the points of contact of rollerand cam-surface to the axis of the respective roller; and the resultantof these pressures biases follower 64 to move upward against thepressure of helical spring 108, which spring maintains contact betweenrollers and earns.

It should be noted that the rollers roll on the cams and on each otherin the proper rotational direction, with but little slippage and wear.

To analyze the motion of rollers 91 and follower 64 under the influenceof the cams, it is convenient to regard the fixed cam-surfaces ofleft-hand ribs 83 as determining the direction of freedom of motion ofthe aXes of the rollers, and to regard the rotation of the right-handcamsurface of movable cam 92 about the axis of shaft 58 as imparting themotion to the rollers.

Thus rollers 91 can be regarded as a species of what may be genericallytermed pressure-transferring means, and the fixed cam surfaces of eitherone of the two pairs of ribs 83 can be regarded as a species of guidemeans, and the opposite cam surface of movable cam 92 can be regarded asa species of impelling means; whereby the pressure of the impellingmeans against the pressure-transferring means causes the latter to movealong the path of motion determined by the guide means, thus causing thefollower to move upward in opposition to the downward biasing effect ofspring 108.

The moving point of contact between the movable cam surface and thesurface of the righthand roller, serves as a toggle joint between twolever, arms: (1) the radius of the roller at the point of contact; (2) aline from the center of shaft 58 to the point of contact. The latterlever arm increases in length when the point of contact lies on one ofthe two flat portions of the movable. camsurface.

Increase in the angle at the toggle joint, serves to drive the rollersaway from the axis of shaft 58. So also does the lengthening of thesecond mentioned arm.

The two cam surfaces are so proportioned and disposed with respect tothe rollers, that the combined effect of the two mentioned actions is tocause the movement of the rollers, along their lines of freedom ofmotion, to be very rapid duringthefirst about 10 degrees of rotation ofshaft 58, this movement decelerating thereafter, and becoming almostzero as the lever arms approach toggle in Fig. 30.

The fact that, while the point of contact is on the second straightportion ofthe moveable cam, the direction of travel of this point ispractically radial with respect to shaft 58, preventsany cumulation ofthe two actions from producing acceleration during this period.

Thus far the discussion has related to the motion of the axes of rollers91, rather than to the motion of follower 64, which is, what is ofimportance. Deceleration of the latter during the final part of thetravel, is accentuated by the change in angle between the .line ofmotion of the follower and the lines. of motion of the axes of therollers. For due to the fact that that angle (which is practically thesameas the inclination of carnsurface 83-to the vertical) is about 17during the first 12 /2 degrees or so of shaft rotation, and about 45during the rest of the shaft rotation, the velocity of the follower isonly about 4 /2% less than the velocity of the roller axes during thefirst period, whereas it is about 30% less during the rest of itstravel.

The rapid initial upward motion of follower 64, followed by decelerationat an increasing rate thereafter, is well illustrated by a comparison ofFigs. 27 to 30, which (as already stated) respectively show thepositions of the parts with shaft 58 at dead-center, and 5 degrees, 40degrees, and 55 degrees counterclockwise from deadcenter. For example,the travel of follower 64 is less than half as far during the final 15degrees of rotation of shaft 58 (Fig. 29 to Fig. 30) than during thefirst 5 degrees of rotation (Fig. 27 to Fig. 28).

The rapid travel during the first 5 degrees persists, and in fact issomewhat intensified, during the rest of the time during which the firststraight portion of cam 92 is in contact with right-hand roller 91 asshown in Figs. 27 and 28: i. e., during about the first 7 /2 degrees ofrotation, althought the actuated switch is supposed to be tripped withinthe first 5 degrees. This ensures a quick trip of the switch, evenshould the parts of the actuating mechanism become worn.

From about 7 /2 degrees to about 35 degrees, righthand roller 91 iscontacted by the first angular point of cam 92.

From about 35 degrees to about 42 /2 degrees, righthand roller 91 iscontacted by the second straight portion of cam 92, as shown. in Fig.29.

And during all the remainder of the rotation, up to 55 degrees as shownin Fig. 30.

We have already seen, during the discussion of the centering mechanism,that rotation of shaft 58 beyond 55 degrees from dead center, isprevented by projection 103 on each of spring-levers 74 strikingshoulder 79, see Fig. 5. The contact between cam 92 and right-handroller 91 has not yet reached toggle between the axis of this roller andthe axis of cam 92. If that contact had passed toggle, the downward biasof spring 168 of follower 64 would force the roller to the right anddown the curved slope of cam 92, and thus would oppose the centeringaction of centering spring 76, when the outside stimulus was removed.

The second species of the invention will now be described.

The description of Figs. 1, 2, and 3 is equally applicable to the secondspecies. So also is the description of the centering mechanism, shown indetail in Figs. l9 to 24, and in the squared right-hand end 95 of shaft58 in Figs. 16 and 17, and shown. assembled in Fig. 5 and in theright-hand portion of Fig. 25.

Operating head casing 111 will now be described, with reference to Figs.31 to 33, 44 and 45.

The front and rear elevations of this casing appear the same as the rearand front elevations of correspondingd Easing 51 of the first species,as shown in Figs. 5 an Turning now to Fig. 31, the plan view of casing111, and the two vertical sections thereof, Figs. 32 and 33, it will beseen that 80 are four holes for screws 53, and 81 are two holes fordrive screws 55, as in the first SPECIES.

Ledges 113 serve as pivot-seats for the cams, which will be hereinafterdescribed. The sides of recesses 114 serve, at their upper ends, toguide the cams against lateral movement, and these recesses are carriedon through to the bottom of casing 111 for no other reason than ease inmanufacture. Thesides of recesses 115 serve to guide thefollower 117which will be hereinafter described.

69 are holes for shaft 118. 71 is a cavity for a bearing 72 hereinafterdescribed, for shaft 111. 73 is a cavity, to hold the entire centeringspring assembly, which 9 may be identical to that of the first species,as shown in Figs. and 25.

Figs. 34, 35, and 36 show respectively an edge elevation, a sideelevation, and a plan view of follower 117. This follower has four legs119. In each side there are two aligned slots 120, which serve asbearings for axles 90 of rollers 91, and to permit these axles to slidelaterally, so that the rollers can constantly engage each other and therespective cam surfaces, as will be hereinafter described. Not as muchlateral play of the axles is necessary in this second species as in thefirst species, but there is no reason why the slots 120 could not formone continuous slot like 89 of the first species. Each axle is free toslide lengthwise of its roller, as in the first species. When follower117 is assembled in casing 111, the side wall of each of the tworecesses 115 maintain the axles in the rollers.

Figs. 37, 38, and 39 show respectively an edge elevation, a plan view,and a side elevation of cam 116. These cams are two in number.

Sharp edge 121 of the wide portion 122 of each cam 116 serves as a pivotfor that cam, as will be hereinafter explained. The lower portion 123 ofeach cam is slightly narrower than half the width of the wide portion,so as to enable the two narrow portions to cross each other whenassembled in the casing.

Hereinafter, so much of one of the wide faces of each cam as liesbetween the letters H and I will be referred to as the first cam-surfaceof that cam, and so much as lies on the opposite face between theletters I and K will be referred to as the second cam-surface.

Figs. 40, 41, 42, and 43 show respectively a left-hand end view, a sideelevation, a transverse cross-section, and a plan view of shaft 118. 94is a slot for a screwdriver, as in the first species. 95 is a squaredportion, to receive certain elements of the centering spring assembly,as explained with respect to the first species. 125 is another squaredportion, which serves as a cam surface to actuate cams 116, as will behereinafter explained. Fig. 42 may be considered as a cross-section ofeither squared portion 95 or squared portion 125.

.124 are two grooves in the shaft to receive the legs 119 of follower117, when assembled, thus locking the shaft in place as will behereinafter explained.

The assembling of the operating-head mechanism will now be explained,with particular reference to Figs. 44 and 45. Reference will also benecessary to some of Figs. 31 to 43, from time to time.

Shaft 117 is first inserted through holes 69 in casing 111. Bearing 72and bushing 56 are then applied over the lefthand end of the shaft, andare secured in place by screws 57.

Cams 116 are then inserted, each with its sharp pivot edge 121 restingon one of pivot-seats 113, and with its lower portion crossing oversquared portion 125 of shaft 118, as shown in Fig. 45.

Follower 117 is then inserted, legs 119 down, from the top. Its legswill straddle shaft 118, and slide in grooves 124 of the shaft, thussecuring the shaft. against longitudinal shift in either direction.

Lever 61 can be secured at any time, as shown in Figs. 1 and 2, andexplained in connection with the first species.

The centering-spring assembly is assembled in cavity 73 and is operated,all as explained in connection with the first species, and shown inFigs. 5 and 25.

The final step in assembly is the placing of helical spring 108 andcover plate 54, as explained inconnection with theffirst species.

Follower 117 is reciprocated in the manner disclosed in greatly enlargedFigs. 46 to 49. Fig. 46 shows the position of the elements with shaft118 on dead-center. Figs. 47, 48, and 49 show the changing position ofthe elements as the shaft is rotated counterclockwise 5 degrees, 40degrees, and 55 degrees respectively. These angles. were chosen forthese figures, for comparison with corresponding Figs. 27 to.30 of thefirst species.

Upward motion of follower 117 is effected by pressure on rollers 91 asthey are squeezed between the cam-surfaces of cams 116. In other words,each cam-surface presses on its respective roller 91 in the direction ofradii extending from the points of contact of roller and camsurface tothe axis of the respective roller; and the resultant of these pressuresbiases follower 117 to move upward against the pressure of helicalspring 168, which spring maintains contact between rollers and earns.

As in the first species, the rollers roll on the cams and .On each otherin the proper rotational direction, with but little slippage and wear.

Although in this second species the rollers are squeezed between twomovable cams 116 moving toward each other, as contrasted with the firstspecies, in which the rollers are squeezed between a fixed cam 83 and amovable cam 92 moving toward it; yet in both species there is relativemovement of the cam-surfaces toward each other. Furthermore, in thesecond species, either one of the two cams 116 can be regarded asprescribing the direction of freedom of motion of the axes of therollers, and the other of these two cams 116 can be regarded asimparting the motion to the rollers.

Thus, as explained in connection with rollers 91, fixed cams 83, movablecam 92, and spring 108, of the first variant: rollers 91 of the secondvariant can be regarded as pressure-transferring means, the uppercam-surface of either one of the two cams 116 can be regarded as guidemeans, and the upper cam-surface of the other cam 116 can be regarded asimpelling means.

The two cams 116, by virtue of crossing each other, have a sort ofscissors action. The two cam-surfaces which engage the rollers, faceeach other. There are also two second cam-surfaces, which face eachother and embrace squared portion of shaft 118.

As shaft 118 rotates in either direction (counterclockwise rotationbeing shown in Figs. 46 to 49), the squared portion acts as a cam, tospread the lower ends of the two cams 116 apart, and thus move the firstcam-surfaces toward each other. The points of contact between shaft 118and the second (i. e., lower) cam-surfaces of cams 116, are initiallytwo corners of squared portion 125; and these points of contact move ina circular are about the axis of the shaft. The component of each ofthese motions which tends to push the respective cam-surface away fromthe other is perpendicular to the cam-surface, and this componentbecomes less and less. Thus in rotating through the first 5 degrees (i.e., from Fig. 46 to Fig. 47) the spreading component is about 75% of themotion of the point of contact. Whereas in Fig. 48 the spreadingcomponent of the left-hand point is practically zero, and of theright-hand point is negligible. And in Fig. 49 both components are zero.

There will now be discussed the effects of the difference in length anddirection of the respective lever-arms of the two cams 116, with respectto squared surface 125 of shaft 118. Each such lever-arm extends fromthe pivot-edge 121 of the cam to the point of contact of shaft 118 withthe cam. These differences appear to be considerable in vFig. 47, and itmight be thought that this would introduce considerable asymmetry ofmotion of the two cams.

But such is not the case. For the two differences have a very nearlyoffsetting elfect, as will be seen by comparing the positions of thelower ends of the two cams 116 in each of Figs. 46 to 49. Thus themotion of the two cams, as well as their configuration, is practicallysymmetrical.

Although, on each cam, the upper cam-surface is on the opposite side ofthe cam from the lower cam-surface,

yet the cross-over of the two cams, scissors-fashion, causes the twoupper cam-surfaces to face each other, and like wise the two lowercam-surfaces. So the spreading-apart of the twolower cam-surfaces causesthe two upper camsurfaces to approach each other. 7 I

The positioning of the cam-pivots 121'above thejcrossover point andlaterally spaced from each other' (-instead of at the cross-over point,as would be expected in a scissors mechanism) causes the angle betweenthe two upper earn-surfaces to increase as these two surfaces approacheach other (rather than to decrease as would be expected in a scissorsaction).

This change in angle causes the upward motion of the rollers todecelerate, in proportion to the movement of the cams. And, as alreadyseen, the movement of the cams decelerates to zero, in proportion to therotation of shaft 118 from dead-center. Thus these two effects cumulateto cause the upward movement of the rollers, and hence of follower 117,to be very rapid during the initial rotation of shaft 118,-this'movementdecelerating thereafter, and becoming zero as the elements assume theposition of Fig. 49.

The already mentioned practical symmetricality of the motion of theupper cam-surfaces of the two symmetrical cams 116, prescribes a pathof'motion for the rollers nearly identical to the path of motion offollower 117 that the rate of travel of the follower isindistinguishable from that of the rollers. The slight departure fromvertical of the path of therollers is easily talr'en-up by the alreadymentioned looseness of their bearings.

The amount of travel of follower 117 during the early degrees ofrotation of shaft 118 from dead center, can be adjusted, while stilldecelerating to zero at 55 degrees, by changing the initial anglebetween the upper cam-surfaces of cams 116, or at least the initialangle between the lower portion of those surfaces. The smaller thisangle, the sharper will be the initial rise of the follower.

There is no passing through toggle analogous to that described inconnection with the first species. Thus shoulders 79 (see Fig.Sidescribed as preventing passing through toggle in the first species ofthe. invention, are not necessary for that purpose in the secondspecies. But they are useful in preventing undue strain on centeringspring 76, though they might be omitted if further overtravel weredesired for any reason.

The first species represents the best mode now contemplated by theinventor of carrying out his invention. The second species,-althoughperhaps more simple to understand, and slightly less expensivetomanufaeture, is not only less easy to assemble, but also its cams 116are less easy to make uniform. These cams are stamped out, and thenformed. Forming them is not difficult, but the thickness of the stockfrom which they are formed is apt to vary beyond tolerance. Also thescraping of the corners of squared portion 125 of shaft 118 on the lowercam-surfaces of cams 116 causes wear; no such cause of wear existsanywhere in the first species, specimens of which have undergone as manyas twenty-fivernillion complete reciprocations, eachwi'thout discernablewear on any of the parts.

However, the second species, although not preferable to the firstspecies, is quite acceptable.

It will be readily evident from the foregoing description that theinvention affords a novel and useful conversion mechanism, by which therotary reciprocation of an externally actuated rotary member can beconverted into translation of a member which is used to actuate someother mechanism.

Now that two embodiments of the invention havebeen shown and described,and several variations therefrom have been suggested, it is to beunderstood that the invention is not to be limited to the specific formsor arrangements of parts herein shown and described.

What is. claimed is: p I p I. In an actuating mechanism, the combinationcomprising: a support; an externally actuable rotatable member mountedon the support for limited rotation backand-forth with respect to thesupport;'a follower slidably mounted on the support for substantiallylinear reciprocation with respect thereto, for output of linear motion;and means for converting the rotary motion of the rotatable member intotranslation of the follower, said converting means comprising: meansbiasing the follower to translate in one given direction; a pair ofinterengaging rollers journaled on the follower side by side laterallywith rspect thereto; and at least one pair of cams carried by thesupport with their cam-surfaces facing each other, each surface rollablyengaging one of the rollers and relatively movable toward each other inresponse to the rotation of the rotatable member, the two cam-surfaceshaving such conformations and being so disposed relative toeaeh otherand to the rollers that as the two camsurfaces are moved toward eachother the resultant of the pressures of the two cam-surfaces on theirrespective rollers will translate the follower in opposition to thebiasing means.

2. Mechanism according to claim 1, wherein the two cam-surfaces havesuch conformations and are so disposed relative to each other and to therollers that, as the two cam-surfaces are moved toward each other,uniform velocity of the rotatable member will at first be converted intorapid translation of the follower which translation will be speedilydecelerated thereafter.

3. Mechanism according to claim 1, wherein the rollers are looselyjournaled, to ensure contact between them and between each roller andits respective cam-surface under pressure of the cam-surfaces.

4. Mechanism according to claim 1, wherein one cam of the pair of camsis held rigid with respect to the support, the other cam being moveablewith respect to the support.

5. Mechanism according to claim 4, wherein the moveable cam is heldrigid with respect to the rotatable member and rotates with the latter.

6. Mechanism according to claim 5, wherein there are two pairs of cams,each pair having the recited characteristics, one of which pairs of camsengages the two rollers when the rotatable member is rotated in onedirection from dead center, and the other of which pairs of cams engagesthe two rollers when the rotatable member is rotated in the oppositedirection from dead center.

7. Mechanism according to claim 1, wherein one cam of the pair of camsis held rigid with respect to the support, the other cam being movablewith respect to the support, and wherein the rollers are freelyshiftable laterally with respect to the follower member to enable therollers to interengage and to enable the roller which engages thesurface of the rigid cam to continue to so engage.

8. Mechanism according to claim 7, wherein there are two pairs of cams,each pair having the recited chara'cteristics, one of which pairs ofcams engages the two rollers'when therotatable member is rotated in onedirection from dead center, and the other of which pairs of cams engagesthe two rollers when the rotatable member is rotated in the oppositedirection from dead center.

9. Mechanism according to claim 1, wherein the two cam surfaces aresymmetrical with respect to the centerline of the follower member.

10. Mechanism according to claim 9, wherein both cams are separatelypivoted on the support at points remote from the pivot-axis of therotatable member and spaced from each other laterally across the path ofthe follower. a

11. Mechanism according to claim 10, wherein the cam surface on each ofthe two cams is adjacent its pivot; and each cam crosses over the otherat a mid point; and each cam has a second cam surface beyond thecross-over point, said two second cam surfaces facing each other; andthe rotatable member passes between said two second cam surfaces and hasa cam surface operationally engaging said two second cam surfaces.

12. Mechanism according to claim 11, wherein the two second cam surfacesand the cam surface of the rotatable member have such conformations andare so disposed that, as the rotatable member is rotated in eitherdirection from dead center, the cam surface of the rotatable member willspread apart the two second cam-surfaces, thus moving the two firstcam-surfaces toward each other.

13. Mechanism according to claim 12, wherein the two second cam surfacesand the cam surface of the rotatable member have such conformations andare so disposed that, as the rotatable member is rotated in eitherdirection from dead center, uniform angular velocity of the rotatablemember will be converted into increasing the angle between the two firstcam'surfaces at a decreasing rate.

14. In an actuating mechanism, the combination comprising: a support; anexternally actuable member, mounted on the support for limited rotationback-andforth with respect thereto; a follower mounted on the supportfor substantially linear reciprocation with respect thereto; meansbiasing the follower to move in one given direction;pressure-transferring means mounted on the follower for motion therewithand transversely with respect thereto; guide-means engaging thepressure-transferring means for prescribing the path of said motionthereof; and impelling means shiftable toward the guide means by therotation of the externally actuable member and engaging thepressure-transferring means, for moving the pressure-transferring meansalong its said path of motion and thereby causing the follower to movein opposition to the biasing means at velocities predetermined by theconfiguration and relative location of the recited 30 elements.

15. In an actuating mechanism, the combination comprising: a support; anexternally actuable rotatable member, mounted on the support for limitedrotation baclo and-forth with respect to the support; a followerslidably mounted on the support for reciprocation with respect theretofor output of substantially linear motion; means restricting thereciprocation of the follower to a substan tially linear path; meansbiasing the follower to translate in one given direction; a pair ofinterengaging rollers journaled on the follower side by side laterallywith respect thereto in such manner as to be moveable longitudinallytherewith and laterally with respect thereto; guide means consisting ofa camway engaging one of the rollers, for prescribing the paths ofmotion of the rollers; a moveable cam shiftable toward the guide meansby the rotation of the rotatable member and engaging the other of therollers, for imparting motion to the rollers along their prescribedpaths of motion and thereby imparting motion to the follower inopposition to the biasing means.

16. Mechanism according to claim 15, wherein the moveable cam is rigidlyattached to the rotating member and imparts motion to the roller whichit engages by means of toggle action at the line of contact between themoveable cam and the roller which it engages.

17. Mechanism according to claim 16, wherein there is stop means forautomatically preventing said line from passing through toggle.

References Cited in the file of this patent UNITED STATES PATENTS2,681,221 Randol June 15, 1954

